Combination yarn



June 1959 J. L. TAYLOR ET AL 2,890,567

COMBINATION YARN Filed May 24, 1956 I NON-THERMUPLASTIC YARN C N n M N Y ur 3 v R w a T C o n z 3 M M N m. Mm M N INVENTORS JAMES L. TAYLOR 6 By 44WRNC c. BVb'RLV 7 Mna'fl 5 ATTORNEVS tates Patent Office Patented June 16, 1959 COINATION YARN James L. Taylor, Greensboro, and Lawrence C. Byerly, High Point, N.C., assignors, by mesne assignments, to Burlington Industries, Inc Greensboro, N.C., a corporation of North Carolina Application May 24, 1956, Serial No. 586,909 Claims. (Cl. 57-140) This invention relates to a process for producing a combination or composite stretch yarn for use in the production of stretchable fabrics, and to the yarns produced thereby. The yarns of this invention are stretch combination yarns comprising a thermoplastic yarn combined with natural or synthetic yarns, not thermoplastic in nature or having reduced thermoplastic properties.

More particularly, this invention relates to a process whereby a thermoplastic yarn, such as nylon, can be combined with a yarn such as cotton or rayon, and the combination yarn twisted to produce a composite yarn having a lively characteristic sufiicient to impart maximum stretchability to the fabric knit from said yarn. In addition to this substantial stretchability, the fabric knit from the yarn of this invention has superior appearance and feel.

It has been known heretofore that highly twisted thermoplastic yarns, particularly nylon yarns, may be plied, wrapped or core-spun with other yarns of a diiferent nature, such as natural fibers or other synthetic yarns, to produce combination yarns having a degree of stretchability. These prior art processes include the plying of one or more ends of a thermoplastic yarn which has been highly twisted, heat set, and backtwisted, with one or more ends of cotton or other natural or synthetic yarns or blends of such yarns to produce a balanced, stretchable yarn. The degree of stretchability obtained is variable, but generally less than the desired maximum stretchability. In addition, the stretch properties of the nylon yarn are materially offset by the other yarn when the two are plied together, so that the stretch properties of the combined yarn are considerably reduced. Moreover, in any case, the resulting knitted or woven fabric tends to have a grainy appearance or an appearance and feel similar to that of terry cloth, in addition to other undesirable characteristics, which detract from the appearance and salability of the fabric.

In practicing the process of our invention, we ply one or more ends of a thermoplastic yarn with one or more ends of another yarn or yarns. The thermoplastic yarn which we utilize is a raw yarn, in contrast .with the prior art processes, which utilize a thermoplastic yarn which has :been subjected to heat setting and twisting. The use of the unset and untwisted yarn, in accordance with our invention, and at this stage of our process pro duces, after the further treatments discussed below, a yarn having superior stretchability, and consequently imparts superior stretchability to the fabrics produced from this yarn, as well as a marked superiority in the appearance and feel of the fabric.

Further advantages of our process in terms of stretchability, appearance, and feel, result from the fact that instead of merely plying a thermoplastic yarn with a natural yarn, we subject the plied combination yarn to further twisting and heat setting treatment, as discussed more fully below.

The thermoplastic yarn which we utilize will ordinarily be a nylon yarn or other thermoplastic yarn which is capable in and of itself of being heat set and twisted to produce a wild or lively yarn suitable for use in the production of stretchable fabrics. The most suitable yarns in this respect are polyamides, caprolactins, polyesters, and polyurethanes, and include particularly nylon and Dacron. These yarns are defined as follows:

Nylona long-chain synthetic polymeric amide which has recurring amide groups as an integral part of the main polymer chain, and which is capable of being formed into a filament in which the structural elements are oriented in the direction of the axis.

Dacron-condensation polymer of ethylene glyco. with terephthalic acid.

Of the various types of nylon, nylon 6 (made by the self-condensation of aminocaproic acid or by polymerization of caprolactarn), and nylon 66 (the condensation polymer of hexamethylene diamine with sebacic acid) are particularly suitable.

' In addition to the above mentioned yarns, any other thermoplastic yarn, which becomes plastic upon the application of heat, and which is capable of being heat set at relatively high temperatures, may be utilized. The essential characteristic is that the yarn must have a memory, that is, it must be capable of being heat set in a particular form and will substantially return to the form in which it was heat set, unless restrained.

The yarn or yarns with which the thermoplastic yarn is plied may be any one or a combination of yarns having substantially lesser memory characteristics as compared with the above thermoplastic yarn. We mean to include in this category natural yarns, such as cotton, wool, silk, and ramie, as well as synthetic yarns that exhibit memory characteristics only to a lesser extent, such as rayon, acetate, etc. We also mean to include in this category yarns various blends of these yarns, which may consist in part of a thermoplastic material. For example, this yarn may be a blend of Dacron and cotton, depending upon the desired end product.

The thermoplastic yarn, defined as above, is plied with the second yarn. In the plying operation, the twist imparted to the combined yarns is of a relatively low order, for example, from 2 to 10 turns per inch. Thereafter, a further twist in the same direction is imparted to the plied yarns. This second, or further twisting, is of a relatively high order. The range of this second twist may vary, depending to some extent, upon the twist inserted during the plying operation. However, upon completion of the twisting operation, the combined yarn will have a relatively high twist. For example, the normal range of twist would be from approximately 30 to turns per inch, depending upon the denier of the yarn and various other factors. In particular cases, and if a coarse yarn is used, the twist may be below 30 turns, or if a fine yarn is used, the twist may be above 80 turns.

, The plying and high twisting operation may be accomplished in one step. For instance, the yarns could be plied and the high twist inserted on a ring twister. However, the procedure which we have first described is more economical, namely, first plying the yarns a relatively low number of turns and then increasing the twist to a relatively high number of turns.

Following the above mentioned plying and twisting, the combined yarn is placed on packages, which may be either rigid or collapsible, and subjected to temperatures sufficient to set the twisted yarn. This heat setting may be accomplished by conventional means, e.g., the yarn may be subjected to steam for a period of time sufficient to set the twist.

After the heat setting of the combined yarn, the heat set combination yarn is untwisted, or backtwisted. This backtwisting step may vary substantially in extent. For instance, the yarn may be backtwisted a lesser number of turns, the same number of turns, or a greater number of turns, than the number of turns which were originally inserted in the opposite direction.

Generally, however, we have found it desirable to backtwist thecombined yarn a greater numberof turns than the number of turns which were originally inserted, and best results are obtained when the yarn is twisted approximately 1 to 12 turns past zero.

As an alternative to the procedures just described, the combined yarns, either before or after plying, may be processed on false twister spindles, in such a manner that the combined yarn is twisted the desired number of turns in one direction, heat set, and the twist backed out, in a continuous operation. In this case, however, it will generally be desirable to impart an additional few turns of backtwist per inch.

In addition to the process described above for producting a combination yarn, namely, the plying of a thermoplastic yarn with a second yarn, the high twisting of the combined yarn, followed by heat setting and backtwisting, there is an alternative procedure whereby the combination yarn of our invention can be produced. In this alternative procedure, the raw thermoplastic yarn can be heat set and subsequently plied, in the absence of substantial twist, with the second yarn and the resulting combination yarn twisted a relatively high number of turns. However, the yarns produced by this alternative procedure tend to be harsh, and the fabrics produced therefrom may be suitable for some industrial uses, but are not generally suitable for wearing apparel.

The resulting yarn may be used singly, and knitted in alternating courses with a yarn having the opposite twist, or twist torque, to produce a balanced fabric having excellent stretch properties and appearance and feel.

Alternatively, the twisted composite yarn may be used in combination with another yarn having the opposite twist, or twist torque. In this case, the two yarns of opposite twist or twist torque, are plied together a relatively low number of turns, for example, about 2 to turns per inch. The resulting yarn is especially desirable for circular knitting, half hose knitting, and weaving.

Whether the combination yarn is used singly, and knit in alternating courses with another yarn, or whether it is plied with another yarn to produce a balanced yarn, the other yarn with which this combination yarn is plied need not be a combination yarn, but may be in either case a thermoplastic yarn which has been heat set and twisted to impart a torque or liveliness to the yarn, and the torque of this other yarn should be about equal to the torque of the combination yarn with which it is used. The twist or twist torque of this yarn should be in a direction opposite to the torque of the combination yarn.

The following are illustrative but non-limiting examples of my invention:

Example I One end of 70 denier, 34 filament, semi-dull nylon yarn, having a producers twist of one-half turn Z is plied approximately 2 /2 turns per inch 2 twist with an end of 75.9 count, single strand combed peeler cotton. This plied or combined yarn is then twisted an additional number of turns(approximately 65)-in the same direction as the plied twist. The yarn is wound on either rigid or collapsible packages, placed in an autoclave and subjected to steam at a temperature of approximately 260 F. for a period of about thirty minutes, sufficient to set the twist in the combined yarn.

After the heat setting treatment, the yarn is backtwisted, or twisted in the opposite direction, about 75 /2 turns, that is, the yarn is untwisted to zero and then an additional 8 turns in the opposite direction, usually, although not necessarily, in one operation.

The yarn so produced may be knit in a fabric in its present form, and knitted in alternating courses with a yarn having the opposite twist or twist torque, and the resulting fabric will have the above mentioned maximum stretchability and attractive appearance and feel.

Alternatively, the yarn so produced may be plied 2 /2 turns per inch 5 twist with an end of 70 denier 34 filament nylon yarn which has been twisted turns per inch 8 twist, heat set as above described and untwisted or backtwisted approximately 77 /2 turns 2 twist Example II One end of denier 34 filament semi-dull nylon yarn having a producers twist /2 turn per inch is plied 1 /2 turns in an 8 direction with one end of 100 denier bright rayoncontaining a normal spinning twist. The twist in the combined or plied yarn is increased to a total of 55 turns 5 twist. The resulting highly twisted yarn is then heat set as described above in Example I. Thereafter, the yarn is untwisted or backtwisted approximately 60 turns, i.e., about 5 turns past zero in the opposite direction.

Although the drawings illustrate the use of a nonthermoplastic yarn, it is to be understood that thermoplastic yarns having lesser memory characteristics, such as previously described, may also be used as the second yarn. The process and product of the present invention are further illustrated in the accompanying drawing, in which:

Fig. l is in enlarged diagrammatic view of the combination yarn, after initial plying of the thermoplastic yarn 1 with the substantially non-thermoplastic yarn 2.

Fig. 2 is a similar view showing the same yarn after the insertion of high twist; and

Fig. 3 shows the same yarn, after heat setting and twisting in the opposite direction from the first twist. This is the final combination yarn product, which may, if desired, be plied with another similar yarn of opposite torque.

The yarn produced according to this example is desirable for circular knitting, for weaving, and, if knitted in conjunction with yarns possessing opposite torque properties, it is also suitable for half hose knitting.

In addition to the foregoing examples, many other desirable combinations are possible, within the scope of our invention.

The raw thermoplastic yarns utilized in the process of our invention are continuous filament yarns, either monofilament or multifilament. The second yarns may be either filament or spun.

The yarns of our invention are desirable and useful in the manufacture of half hose, bathing suits, underwear, particularly mens underwear, and foundation garments, as well as numerous other articles.

The present invention has been described above in detail for purposes of illustration only and is not intended to be limited by this description or otherwise except 3 defined in the appended claims.

We claim:

1. A stretchable composite yarn for use in a stretchable fabric, comprising at least one thermoplastic yam having substantial memory characteristics and yarn having substantially no twist prior to plying, plied with at least one yarn having lesser memory characteristics, said composite yarn having been heat set and subsequently twisted without further heat setting.

2. A stretch composite yarn for use in a stretchable fabric, comprising at least one thermoplastic yarn having substantial memory characteristics which has been heat set and subsequently plied, in the absence of substantial twist, with a yarn having lesser memory characteristics and the plied yarns twisted a plurality of turns without furthe: heat setting.

3. A stretch composite yarn for use in a stretchable fabric, comprising at least one thermoplastic yarn having substantial memory characteristics and having substantially no twist prior to plying, and at least one yarn having lesser memory characteristics, said yarns having been plied together, and twisted a plurality of turns in one direction, then heat set, and subsequently twisted a plurality of turns, in the opposite direction.

4. A ply yarn in which at least one of the plies consists of a composite yarn as defined in claim 3.

5. A stretchable composite yarn for use in stretchable fabric, consisting of two combination yarns plied together, each of said combination yarns consisting of a thermoplastic yarn having substantial memory characteristics plied with a yarn having lesser memory characteristics and twisted a plurality of turns in one direction, then heat set and subsequently twisted a plurality of turns in the opposite direction, the final twist in one of said combination yarns being in a direction opposite to the direction of final twist in the other of said combination yarns.

6. A process for producing a stretch yarn for use in the production of a stretchable fabric, comprising heat setting in the absence of substantial twist, a thermoplastic yarn having substantial memory characteristics, and plying said yarn with a yarn having lesser memory characteristics and twisting the plied yarns a plurality of turns without further heat setting.

7. A process for producing a stretch yarn for use in the production of a stretchable fabric, comprising plying a thermoplastic yarn having substantial memory characteristics and having substantially no twist prior to plying with a yarn having lesser memory characteristics and twisting said plied yarns a plurality of turns in one direction, then heat setting and thereafter twisting said plied yarns a plurality of turns in the opposite direction.

8. A process of producing a composite stretch yarn in which two stretch yarns of opposite twists and produced by the process of claim 7 are plied together.

9. A composite stretch yarn for use in a stretchable fabric, comprising at least one yarn which after being heat set will substantially return to the form in which it was heat set, said yarn having substantially no twist prior to plying, plied with at least one yarn which will not return to the form in which it was heat set, said composite yarn having been heat set and subsequently twisted without further heat setting.

10. A stretchable composite yarn for use in a stretchable fabric, comprising at least one thermoplastic yarn having substantial memory characteristics and having substantially no twist prior to plying, plied with at least one yarn having lesser memory characteristics, in which at least said thermoplastic yarn has been heat set, said composite yarn having been twisted to an extent sufiicient to impart stretchability to said yarn, and without further heat setting.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Textile World; June 1955; pages 94-97.

unmn STATES PATENT OFFICE 0F CQRREICTION- Patent No, 2,890,567 4 June 16, 1959 James L. Taylor et a1.

It ie hereby certified that error appears in the specification of the above numbered patent requiring correction and thait the said Letters Patent should read as corrected below.

Column-4, line 64, strike out "yarn".

Signed and sealed this 1st day of December 1959.

i (SEAL).

Atieet:

AXLINE ROBERT c. WATSON Attesting Officer Comiasioner of Patents 

